Operational range assignment in sensor and actor networks

Networks of sensors and actors can be used in a variety of applications, including the detection of chemical activity or controlling pests in farms. In these applications, nodes (sensors and actors) are typically deployed in large numbers. Thus, not all of them need to operate at their maximum operational (sensing/acting) ranges, especially when the underlying operation is expensive. In this work, we study how to minimize the operational range in a distributed fashion. Unlike previous work, we consider environments in which location estimation is not possible (e.g., dense forests). We develop a distributed protocol for assigning the operational ranges of nodes (ORAP). ORAPassigns longer ranges to nodes that are less resource constrained (e.g., in terms of energy) than their peers in order to prolong the operational lifetime of every individual node. If the nodes are not aware of their locations, ORAP employs a novel localized algorithm (VICON) for determining the virtual coordinates of the neighbors of each node. VICON relies on conservative estimates of neighbor distances and advertised 1-hop neighborhood information. We show that ORAP introduces negligible overhead and meets its intended goals. Extensive simulations indicate that ORAP balances resource consumption among nodes, resulting in a significant network lifetime improvement even under inaccurate distance estimation.